TM 11-5820-358-35 Field and Depot Maintenance Manual for Radio Receiver R-390A/URR 1961-12-08
"This manual covers field and depot maintenance for Radio Receiver R-390A/ URR. It includes instructions appropriate to third, fourth, and fifth echelons for troubleshooting, testing, aligning, and repairing the receiver and replacing maintenance parts. It also lists tools, materials, and test equipment for third, fourth, and fifth echelon maintenance. Detailed functions of the equipment are covered in the theory section."
Digitized by the Combined Arms Research Library Digital Library, US Army Combined Arms Center. http://cgsc.cdmhost.com/cdm/